When I started on the "project" a 53 3/4 ton GMC I had a heck of a time getting the shifter out of the trans.What I had to do was spray the retainer with some WD40 and tap it down with a plastic hammer,it was packed with sand that had gotten hard from setting for ten years.Once it popped up and down on the spring I just pushed it down and gave it a twist and it came right out.
Pete